外源一氧化氮供体SNP对水稻叶片中由硒引起的脂质过氧化的调节作用

一氧化氮(nitric oxide, NO)是植物中一种重要的信号分子, 在诱导种子萌发, 影响植物生长发育, 促进植物细胞衰亡等方面发挥着重要作用。然而对于外源NO是否参与了Se诱导的脂质过氧化调节过程仍不为人知。我们研究了0.2 μmol L^-1和20 μmol L^-1Na₂SeO₃及一氧化氮供体硝普钠(sodium nitroprusside, SNP)处理对水稻叶片叶绿素、H₂O₂和硫代巴比妥酸反应产物(Thiobarbituric Acid Reactive Substances, TBARS)含量, 愈创木酚过氧化物酶(guaiacol peroxidase, GPX)、超氧化物歧化酶(superoxide dismutase, SOD)、过氧化氢酶(catalase, CAT)以及抗坏血酸过氧化物酶(ascorbate peroxidase, APX)活性等生理生化指标的影响。结果表明, 1 μmol L^-1SNP处理促进GPX、APX和CAT活性, 缓解膜脂过氧化, 降低TBARS含量;显著提高0.2 μmol L^-1Na₂SeO₃处理下水稻叶片中叶绿素含量。在20 μmol L^-1Na₂SeO₃处理下, 外加1 μmol L^-1SNP更加显著促进GPX和CAT活性, 与此同时明显降低20 μmol L^-1Na₂SeO₃处理引起的H₂O₂含量上升, 并降低TBARS含量。NO对植物中由Se引起的脂质过氧化具有调节作用。

Effects of Exogenous Nitric Oxide Donor SNP on Lipid Peroxidation Caused by Selenium in Rice Seedlings

Nitric oxide (NO) is a bioactive molecule that has been suggested to act as a signaling molecular in plants. It induces germination, affects plant growth and development, and promotes plant cell death. NO is also involved in plant response to heat, salinity, ultraviolet-B, and heavy metal stresses. It is known that some effects of NO may relate to the regulation of reactive oxygen species (ROS) metabolism by means of affecting activities of catalase (CAT) with hemachrome iron, and/or guaiacol peroxidase (GPX) with none-hemachrome iron. However, whether NO regulates lipid peroxidation in rice seedlings induced by selenium is not yet understood. In this article, we reported some regulative  effects of exogenous nitric oxide donor SNP on oxidative stresses induced by selenium in rice seedlings. The contents of chlorophyll, H₂O₂, TBARS and the activities of GPX, superoxide dismutase (SOD), CAT and ascorbate peroxidase (APX) in rice seedlings treated with a varying concentrations of seleniumand 1 μmol L^-1SNP were investigated. The results showed that the content of chlorophyll increased by treatment with SNP in 0.2 μmol L^-1Na₂SeO₃ group. SNP alleviated significantlythe lipid peroxidation in rice seedlings via promoting GPX, APX and CAT activities in rice leaf. In 20 μmol L^-1Na₂SeO₃ treated rice seedlings, SNPalleviated significantlyTBARScontent and the increase of H₂O₂ content that resulted from high selenium stress via promoting GPX, especially APX and CAT activities. Taken together, our results suggested that NO regulates lipid peroxidation caused by selenium in rice seedlings.